I. Field of the Disclosure
The technology of the disclosure relates generally to voltage level shifters for shifting signals in one voltage domain to another voltage domain, and particularly to reducing transition times of shifting such signals in voltage level shifters.
II. Background
Processor-based systems have access to a power supply that provides voltage for powering operations. Particular components within a processor-based system may operate while using less voltage as compared to other components within the same system. For example, a processor may use less voltage to operate during idle modes. On the other hand, memory may indicate a certain minimum voltage to retain data, regardless of the processor's mode of operation. In this regard, rather than providing a single voltage supply to supply a voltage to all components in a processor-based system equally, more than one voltage supply may supply voltage to components of the processor-based system. Components that can operate at a lower voltage are powered by a lower voltage supply in a first voltage domain, while components that can operate at a higher voltage are powered by a higher voltage supply in a second voltage domain. In this manner, power is conserved as opposed to providing a single higher voltage to all components.
However, so that signals from components in one voltage domain operating from a first voltage supply can be compatibly provided and processed by components operating from a second voltage supply in another voltage domain, voltage level shifters are employed. Voltage level shifters shift signals from a first voltage domain to a second voltage domain, or vice versa. For example, voltage level shifters can shift a logic high (‘1’) voltage in the first voltage domain (e.g., 0.5 V) to a logic high (‘1’) voltage in the second voltage domain (e.g., 1.0 V).
Notably, as the difference in supply voltages in the second voltage domain and the first voltage domain increases, components within a voltage level shifter must be configured so as to prevent concurrent activation of certain components. For example, as the difference in supply voltages in the first and second voltage domains increases, an input signal in the first voltage domain may concurrently activate a pull-down circuit and a pull-up circuit in a voltage level shifter. To prevent such concurrent activation of the pull-down and pull-up circuits, the pull-down circuit can be configured to be stronger than the pull-up circuit at driving the output. Conventionally, in order to configure the pull-down circuit to be stronger than the pull-up circuit at driving the output, the pull-down circuit may be designed with a larger size, thus resulting in an increase of overall area of the voltage level shifter. It would be advantageous to provide a voltage level shifter to prevent concurrent activation of components as the difference in supply voltages of the first and second voltage domains increases while mitigating or eliminating increase in area.